Geometric phase-assisted simple phase compensation enabling quantum key distribution using phase-shifted Bell states

• URL: http://arxiv.org/abs/2604.12272v1
• Date: Tue, 14 Apr 2026 04:35:36 GMT
• Title: Geometric phase-assisted simple phase compensation enabling quantum key distribution using phase-shifted Bell states
• Abstract summary: Entanglement-based quantum key distribution relies on the distribution of maximally entangled Bell states.<n> unwanted relative phases arise from birefringence, pump-beam contributions, imperfect photon-pair generation, transmission through physical channels, and collection.<n>We demonstrate a simple and versatile phase-compensation scheme that can be implemented at either the source or the receiver.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Entanglement-based quantum key distribution (QKD) relies on the distribution of high-fidelity maximally entangled Bell states, typically generated via spontaneous parametric down-conversion (SPDC). In practical systems, unwanted relative phases arise from birefringence, pump-beam contributions, imperfect photon-pair generation, transmission through physical channels, and collection, transforming Bell states into phase-shifted states. This degrades interference visibility, increases the quantum bit error rate (QBER), and limits secure key generation. Conventional compensation techniques, such as birefringent crystals, interferometric stabilization, and spatial light modulators, are often impractical in real-world deployments. Here, we demonstrate a simple and versatile phase-compensation scheme that can be implemented at either the source or the receiver to eliminate arbitrary relative phases in Bell states. We theoretically and experimentally quantify the dependence of QBER in the BBM92 protocol on the relative phase and show that geometric-phase-based control can effectively restore entanglement quality. In a proof-of-concept experiment using a nondegenerate polarization Bell state, we achieve a fidelity exceeding 95% and reduce QBER below the 11% security threshold required for secure QKD. This robust approach enables practical phase control in entangled-photon systems and can be extended to time-bin QKD via time-polarization mapping, offering a promising route toward stable, low-QBER quantum communication.

Related papers

• Bayesian Phase Stabilization at the Shot-Noise Limit for Scalable Quantum Networks [19.00377679182238]
  High-precision optical phase stabilization in quantum networks is constrained by strict photon-flux and duty-cycle limits.<n>We develop an integrated phase-stabilization framework that incorporates a Bayesian phase estimator to optimally extract information from sparse single-photon detection events.<n>This work establishes a robust and scalable foundation for practical long-distance quantum networks.
  arXiv  Detail & Related papers  (2026-04-23T07:57:24Z)
• Continual Quantum Architecture Search with Tensor-Train Encoding: Theory and Applications to Signal Processing [68.35481158940401]
  CL-QAS is a continual quantum architecture search framework.<n>It mitigates challenges of costly encoding amplitude and forgetting in variational quantum circuits.<n>It achieves controllable robustness expressivity, sample-efficient generalization, and smooth convergence without barren plateaus.
  arXiv  Detail & Related papers  (2026-01-10T02:36:03Z)
• Implementing a Universal Set of Geometric Quantum Gates through Dressed-State assisted STA [39.27725073249277]
  We analyze the implementation of single-qubit gates in a two-level system driven by a microwave field.<n>We show how the dynamical phase can be canceled to obtain purely geometric operations.<n>We extend the protocol to construct non two-qubit gates, highlighting its feasibility for scalable quantum information processing.
  arXiv  Detail & Related papers  (2025-09-10T16:14:34Z)
• A Metropolitan-scale Multiplexed Quantum Repeater with Bell Nonlocality [6.71684079581608]
  Quantum repeaters can overcome exponential photon loss in optical fibers, enabling heralded entanglement between quantum memories.<n>Bell nonlocality is a cornerstone for device-independent security and foundational tests of quantum mechanics.<n>Here, we report the heralded entanglement distribution between two solid-state quantum memories separated by 14.5 km.<n>We generate a Bell state with a fidelity of $78.6pm2.0 %$, achieving a CHSH-Bell inequality violation by 3.7 standard deviations.
  arXiv  Detail & Related papers  (2025-08-25T12:08:05Z)
• Rotational-invariant quantum key distribution based on a quantum dot source [0.0]
  Single-photon quantum emitters offer remarkable on-demand photon emission, near-unitary indistinguishability, and low multiphoton generation.<n>Our findings suggest a viable direction for the use of rotational-invariant hybrid states in on-demand QKD protocols.
  arXiv  Detail & Related papers  (2025-06-29T10:13:38Z)
• Bayesian Quantum Amplitude Estimation [46.03321798937855]
  We present BAE, a problem-tailored and noise-aware Bayesian algorithm for quantum amplitude estimation.<n>In a fault tolerant scenario, BAE is capable of saturating the Heisenberg limit; if device noise is present, BAE can dynamically characterize it and self-adapt.<n>We propose a benchmark for amplitude estimation algorithms and use it to test BAE against other approaches.
  arXiv  Detail & Related papers  (2024-12-05T18:09:41Z)
• High-quality entangled photon source by symmetric beam displacement design [39.58317527488534]
  Entangled photon sources are pivotal in advancing quantum communication, computing and sensing. This work introduces a polarization-entangled photon source, leveraging type-0 spontaneous parametric down-conversion. We attained a maximal Bell inequality violation, with the average entanglement visibility exceeding 99%.
  arXiv  Detail & Related papers  (2024-07-04T10:29:47Z)
• Multiplexed quantum repeaters based on single-photon interference with mild stabilization [0.0]
  We present a quantum repeater scheme that leverages single-photon interference with reduced difficulty of phase stabilization. Under specific conditions, we demonstrate that our scheme achieves a higher entanglement distribution rate between end nodes compared to existing schemes.
  arXiv  Detail & Related papers  (2024-01-17T19:58:28Z)
• Phase-Matching Quantum Key Distribution without Intensity Modulation [25.004151934190965]
  We propose a phase-matching quantum key distribution protocol without intensity modulation. Simulation results show that the transmission distance of our protocol could reach 305 km in telecommunication fiber. Our protocol provides a promising solution for constructing quantum networks.
  arXiv  Detail & Related papers  (2023-03-21T04:32:01Z)
• Towards Fully Passive Time-Bin Quantum Key Distribution over Moving Free-Space Channels [36.136619420474766]
  Quantum information in photonic time-bin states is typically considered impractical for moving free-space quantum communication.<n>We demonstrate a novel approach using reference frame independent time-bin quantum key distribution.<n>The scheme can be readily applied over various spatially multi-mode and fluctuating channels involving rapidly moving platforms.
  arXiv  Detail & Related papers  (2023-02-10T03:53:21Z)
• Protecting the quantum interference of cat states by phase-space compression [45.82374977939355]
  Cat states with their unique phase-space interference properties are ideal candidates for understanding quantum mechanics. They are highly susceptible to photon loss, which inevitably diminishes their quantum non-Gaussian features. Here, we protect these non-Gaussian features by compressing the phase-space distribution of a cat state.
  arXiv  Detail & Related papers  (2022-12-02T16:06:40Z)
• Fibre polarization state compensation in entanglement-based quantum key distribution [62.997667081978825]
  Quantum Key Distribution (QKD) using polarisation encoding can be hard to implement over deployed telecom fibres. We show a technique for dynamically compensating fibre-induced alteration in a QKD system over deployed fibre.
  arXiv  Detail & Related papers  (2021-07-16T00:53:48Z)
• Round-robin differential phase-time-shifting protocol for quantum key distribution: theory and experiment [58.03659958248968]
  Quantum key distribution (QKD) allows the establishment of common cryptographic keys among distant parties. Recently, a QKD protocol that circumvents the need for monitoring signal disturbance, has been proposed and demonstrated in initial experiments. We derive the security proofs of the round-robin differential phase-time-shifting protocol in the collective attack scenario. Our results show that the RRDPTS protocol can achieve higher secret key rate in comparison with the RRDPS, in the condition of high quantum bit error rate.
  arXiv  Detail & Related papers  (2021-03-15T15:20:09Z)
• Detecting out-of-time-order correlations via quasi-adiabatic echoes as a tool to reveal quantum coherence in equilibrium quantum phase transitions [0.0]
  We show that an abrupt change in coherence and entanglement of the ground state is observable in the spectrum of multiple quantum coherence intensities. Our scheme allows for the detection of OTOCs without time-reversal of coherent dynamics.
  arXiv  Detail & Related papers  (2020-06-01T23:28:44Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.